<html>
    <head>
        <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
        <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
        <title>Google Maps JavaScript API v3 Example: Event Properties</title>
        <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script>
        <script type="text/javascript">
            var map;
            function initialize() {
                var myLatLng = new google.maps.LatLng(-25.363882,131.044922);
                var myOptions = {
                    zoom: 4,
                    center: myLatLng,
                    mapTypeId: google.maps.MapTypeId.ROADMAP
                }
                map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);

                var zoomLevel;
                var infowindow = new google.maps.InfoWindow(
                {
                    content: 'Zoom Level Test',
                    position: myLatLng
                });
                
                //Opens this InfoWindow on the given map.
                infowindow.open(map);

                google.maps.event.addListener(map, 'zoom_changed', function() {
                    //get zoom level
                    zoomLevel = map.get_zoom();
                    map.setCenter(myLatLng);
                    infowindow.setContent("Zoom: " + zoomLevel);
                    if (zoomLevel == 0) {
                        map.setZoom(10);
                    }
                });
            }
        </script>
    </head>
    <body style="margin:0px; padding:0px;" onload="initialize()">
        <div id="map_canvas" style="width:100%; height:100%"></div>
    </body>
</html>
